The biggest non-Glenn Beck joke in American political circles goes thusly: When a male Democrat has an affair it’s with a woman, and when a Republican has an affair it’s with a man. (It’s homophobic in its own way—why do Republicans deserve ridicule for screwing other men?—but you get the point.) Recently, though, that’s just not true. First there was John Ensign’s deafening silence, and then there was Mark Sanford’s inability to stop those torrents of sappy diarrhoea from dumping out his mouth-hole.